The present invention relates to an ultrasonic probe and an ultrasonic diagnostic apparatus.
An ultrasonic diagnostic apparatus whose system has less number of channels than the number of transducer elements is known (e.g. JP-A No. 2004-358105). For instance in an electron scanning type ultrasonic diagnostic apparatus, since every transducer transmits and receives ultrasonic waves all the time, the number of channels on the system side can be less than the number of transducers. In such an ultrasonic diagnostic apparatus, by disposing multiplexer ICs between transducers and system channels for instance, transmission and reception with fewer system channels than the transducers is realized.
However, in such an ultrasonic apparatus, though a multiplexer is connected to every transducer, ON/OFF switching is not performed in every multiplexer. In an electron scanning system for instance, the multiplexer connected to the transducer arranged at the center of a probe may be used in a mode of being kept ON all the time. And since multiplexer ICs are generally expensive, the presence of unused multiplexers might invite an undue cost increase.
On the other hand, since multiplexer ICs also have resistance components such as ON resistors, indiscreet dispensation with a multiplexer IC used in a mode of being kept ON all the time would be detrimental to the uniformity of picture quality. For instance, dispensation with a multiplexer IC would invite an increased signal intensity due to a drop in resistance between the transducer and the system channel and accordingly partially greater brightness of the image.